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Biomedical subjects

K Nakajima

Publications and source records attributed to K Nakajima.

At least 145 records · Page 8Linked to original sources
PubMed2001

Nonpolarizing guided-mode resonant grating filter for oblique incidence.

A new type of guided-mode resonant grating filter is described. The filter is independent of polarization state for oblique incidence. The filter has a crossed grating structure, and the plane of incidence on the filter contains the symmetric axis of the grating structure. Theoretical considerations and numerical calculations using two-dimensional rigorous coupled-wave analysis show that a rhombic lattice structure is suitable to such filters. In this configuration an incident light wave is diffracted into the waveguide and is divided into two propagation modes whose directions are symmetric with respect to the plane of incidence. In particular, when the propagation directions of the two modes are perpendicular to each other, the fill factor of grating structure can be approximately 50%. The filter was designed for an incident angle of 45 degrees. Tolerances of setting errors and fabrication errors for this filter were estimated by numerical calculations.

Journal Article↗
PubMed2001

Acute pericarditis associated with 5-aminosalicylic acid (5-ASA) treatment for severe active ulcerative colitis.

A 17-year-old male who had been diagnosed with ulcerative colitis was prescribed 80 mg prednisolone and 1,500 mg 5-aminosalicylic acid (5-ASA) per day. Two weeks after initiating therapy, he was referred to our hospital for evaluation of chest pain and high fever. Electrocardiography (ECG) showed ST elevation in limb and precordial leads. Chest pain with high fever and ECG changes were resolved after 5-ASA was discontinued. Three weeks later, the administration of a low dose of 5-ASA was associated with the immediate recurrence of pericarditis associated with chest pain, suggesting a hypersensitive reaction to 5-ASA in this patient.

Adolescent↗
PubMed2001

Primary pulmonary hypertension with severe systemic hypertension, Raynaud's phenomenon and relative polycythemia.

A 32-year-old Japanese man was hospitalized for evaluation of unconsciousness. He was diagnosed as having primary pulmonary hypertension (PPH) with severe systemic hypertension, Raynaud's phenomenon and relative polycythemia. Hemostatic studies revealed increased coagulation and decreased fibrinolysis, similar to findings of chronic disseminated intravascular coagulation (DIC). Although activation of coagulation and systemic hypertension were improved after treatment with phlebotomy and administration of nifedipine, enerapril and warfarin, pulmonary hypertension was unchanged, suggesting that irreversible change had already occurred in the pulmonary arteries. Those complications could modify the process of pulmonary hypertension by inducing a hyperviscosity state.

Adult↗
PubMed2001

Gadolinium-enhanced MR imaging in the evaluation of uterine fibroids treated with uterine artery embolization.

OBJECTIVE: The purpose of this study was to determine whether tumor volume reduction can be predicted by the infarction rate of uterine fibroids as seen on gadolinium-enhanced MR images obtained immediately after uterine artery embolization. MATERIALS AND METHODS: In our study, 36 women with symptomatic uterine fibroids successfully underwent uterine artery embolization. Unenhanced and enhanced MR imaging was performed before the procedure and repeated at 1 week, 4 months, and 1 year after the procedure. We retrospectively reviewed enhanced MR images of uterine fibroids after uterine artery embolization. At 4 months after uterine artery embolization, we compared the rate of tumor volume reduction in patients with completely infarcted dominant fibroids with the rate of tumor volume reduction in patients with partially infarcted fibroids. RESULTS: Enhanced MR images obtained 1 week after uterine artery embolization revealed that 100% infarction rates of the dominant uterine fibroids were achieved in 33 women (92%), and 70--90% infarction rates were seen in the remaining three (8%). They also revealed that of a total of 204 fibroids in these patients, 100% infarction was achieved in 199 fibroids (98%). Enhanced MR images obtained 4 months after uterine artery embolization showed that tumor volume reduction of the completely infarcted dominant fibroids (n = 23) was 60% +/- 18%, whereas that of the partially infarcted fibroids (n = 5) was 35% +/- 27% (p = 0.0367). CONCLUSION: Gadolinium-enhanced MR imaging is a useful diagnostic technique for uterine fibroids after uterine artery embolization because it assesses the degree of infarction in the embolized fibroids, which corresponds to the subsequent tumor volume reduction.

Adult↗
PubMed2001

[Assessment by means of a Minimum Data Set of the changes of mental and physical status of elderly patients with dementia during two years of institutionalization].

Using a Minimum Data Set, we studied how the mental and physical conditions of elderly people with dementia changed during two years of institutionalization. Fifty-five patients with dementia of Alzheimer's type (DAT) and 25 with vascular dementia (VD) admitted to the dementia ward in Kyoto Higashiyama Geriatric Hospital were investigated. We assessed them at the time of their institutionalization, and every three months for two years. On institutionalization, a difference between DAT and VD was noted in the group in which more than 10 areas of Resident Assessment Protocols (RAPs) were triggered. The areas of delirium, communication, behavioral problem, activities, activities of daily living, dehydration/fluid maintenance, and psychotropic drugs were evenly triggered in both dementia groups. In the DAT group, however, mood state and dental care were also highly triggered while urinary incontinence, falls and nutritional status were highly triggered in the VD group. Three months later, marked improvements were observed in all of the above areas. However, RAPs areas gradually increased subsequently, and there was marked difference in the areas and their course of progression between the dementia groups. In the DAT group, the trigger rate of the areas of communication, activities of daily living, urinary incontinence, dental care, nutritional status and falls gradually increased after 6 months of evaluation. However, the trigger rate in only three areas, such as communication, visual function and urinary incontinence, become higher, but their patterns of increase were irregular. Mental and physical conditions of the patients with dementia were different in each dementia subtype on institutionalization, but these conditions improved soon after. However, the conditions were gradually became worse, and the pattern was different in each dementia group: DAT showed a slow and steady decline, but VD showed irregular progression and differed among individuals.

Aged↗
PubMed2001

Methods for determination of milt protein and epsilon-polylysine in food additive preparations and processed foods by capillary zone electrophoresis.

A simple and rapid method using capillary zone electrophoresis (CZE) for the determination of milt protein (MP), which contains mainly protamine, and polylysine (PL) in food additive preparations and processed foods was developed. CZE separation was performed on poly(vinyl alcohol)-coated capillaries at a column temperature of 20 degrees C with 120 mmol/L phosphate buffer (pH 2.5) as the running buffer. The influence of various components in food additive preparations on CZE analysis of MP and PL was examined. Egg white lysozyme, glycine, sodium acetate, glycerol, fumaric acid, calcium carbonate, dextrin, emulsifiers and sodium polyphosphate and pyrophosphate had no effect. No peak of protamine was detected in preparations containing metaphosphate. The analysis method for processed foods was composed of extraction with 4% formic acid, precipitation of macromolecular compounds with ethanol, concentration in a water bath and determination by CZE. The average recoveries were 108.4% for protamine sulfate (PS) in red bean sticky rice, and 81.3% for PL in white rice, 118% in egg sandwiches, and 115% in shiraae. The limits of detection of PS in red bean sticky rice and PL in white rice were both 50 ppm.

Electrophoresis, Capillary↗
PubMed2001

Diastolic dysfunction in patients with systemic sclerosis detected by gated myocardial perfusion SPECT: an early sign of cardiac involvement.

UNLABELLED: Diagnosis of cardiac involvement is important for the management of patients with systemic sclerosis (SSc). This study was undertaken to determine the significance of gated myocardial perfusion SPECT in patients with SSc and whether diastolic function measured by gated SPECT is an early sign of cardiac complications. METHODS: Thirty-four patients with SSc and 16 control patients were studied using exercise nongated and resting gated myocardial perfusion SPECT. The SSc was classified by the modified Rodnan total skin score (TSS) into high-TSS (score > or = 10; n = 18) and low-TSS (score < 10; n = 16) groups. Gated SPECT was performed using 99mTc-methoxyisobutylisonitrile with 16 frames per cardiac cycle and quantitatively analyzed by QGS software and Fourier filtering of the volume curve. The parameters of ejection fraction (EF), peak filling rate (PFR), one-third mean filling rate, and time to PFR (TPFR) were calculated. RESULTS: A slight perfusion abnormality was observed in four and five patients in the low-TSS and high-TSS groups, respectively (not statistically significant). A decreased resting EF less than 55% was found in no and two patients in the low-TSS and high-TSS groups, respectively. TPFR was 166 +/- 22, 168 +/- 38, and 216 +/- 82 ms (P = 0.05, high-TSS group versus low-TSS group; P = 0.04, control group versus high-TSS group) and TPFR/R-R interval was 0.18 +/- 0.02, 0.19 +/- 0.04, and 0.26 +/- 0.09 (P = 0.01, high-TSS group versus low-TSS group; P = 0.005, control group versus high-TSS group) for the control, low-TSS, and high-TSS groups, respectively. CONCLUSION: Diastolic function can be evaluated by gated myocardial perfusion SPECT. Significant diastolic abnormalities were shown even in patients with normal perfusion and systolic function and were related to the severity of SSc.

Coronary Circulation↗
PubMed2001

Determination of plasma prothrombin level by Ca2+-dependent prothrombin activator (CA-1) during warfarin anticoagulation.

BACKGROUND AND AIM OF THE STUDY: The carinactivase-1 (CA-1) test is a new method for monitoring plasma prothrombin levels during warfarin anticoagulation therapy. METHODS: A total of 192 patients were allocated to two groups. Group A patients (n = 42) were controls (no warfarin); group B patients (n = 150) received warfarin. A Ca2+-ion and Boc-Val-Pro-Arg-pNA (a chromogenic substrate for thrombin) were added to 10-fold diluted plasma, after which prothrombin was activated with CA-1. Prothrombin levels were determined by measuring the extent of p-nitoroaniline liberation. RESULTS: The mean prothrombin level was 112.8 +/- 20.0 microg/ml in group A (Gaussian distribution), and 53.3 +/- 19.6 microg/ml in group B. In group B, correlations were found between the CA-1 test and prothrombin levels measured by prothrombin time (PT; r = 0.61, p <0. 01), PT-INR (r = 0.61, p <0.01), Thrombotest (TT; r = 0.57, p <0.01) and Hepaplastin test (HPT; r = 0.69, p <0.01). CONCLUSION: The CA-1 test represents a viable method of monitoring the coagulation system. CA-1 recognized the Gla-domain of prothrombin, and activated prothrombin. The CA-1 test required only 10 microl of diluted blood plasma, and took approximately 30 min to complete. The CA-1 test also measures prothrombin levels, correlates excellently with other tests for coagulation, and compares well with currently available methods for determining the efficacy of warfarin.

Aged↗
PubMed2001

[Clinical laboratory data and reference intervals standardized in Fukuoka].

In Fukuoka whose population is approximately five million inhabitants, surveys on the accuracy of laboratory data have been performed by the Fukuoka Prefecture Medical Association for the last 30 years. We have been attempting to evaluate the data for routine use since 1988, and it has become possible to share laboratory data between all institutions in Fukuoka prefectures. As a result, reference intervals for 23 clinical chemistry analytes were established in 1995, to which were added in 1996 five serum protein constituents that have been utilized for clinical examinations. Methods for documentations and monitorings the data obtained in the prefecture were also established, standardization of the above analytes extended to 97% of the institutions in the prefecture. Results for 14 of the 23 clinical chemistry analytes have become highly reliable and clinically useful as differences between institutions in terms of results have narrowed. Standardization of other analytes is now in progress.

Aged↗
PubMed2001

Methylation of the E-cadherin gene promoter correlates with progression of prostate cancer.

PURPOSE: We studied the methylation status of E-cadherin gene promoter in prostate cancer and its relationship with E-cadherin inactivation in prostate cancer. MATERIALS AND METHODS: Seven human prostate cell lines and 35 microdissected prostate cancer specimens were analyzed for E-cadherin promoter methylation using the bisulfite genome sequencing technique. E-cadherin messenger (m)RNA expression and protein expression were also studied in prostate cell lines by reverse transcriptase-polymerase chain reaction and in prostate cancer specimens by immunostaining, respectively. RESULTS: The overall methylation of E-cadherin promoter was evident in 14 of 20 grades III to V (70%) and in 5 of 15 grades I to II (33%) prostate cancer samples. It correlated with absent or reduced E-cadherin immunostaining. Methylation in low grade tumors was present mainly in the exon region, whereas in high grade tumors methylation was also present in the promoter region. Methylation was noted in 2 of 6 prostate cancer cell lines (33%) and correlated well with decreased E-cadherin mRNA in these cell lines. Treatment with the demethylating agent 5-aza-2'-deoxycytidine restored E-cadherin mRNA levels in the E-cadherin negative prostate cancer cell lines TSUPr1 and DuPro. CONCLUSIONS: Methylation of the E-cadherin gene is common in prostate cancer and the severity of E-cadherin methylation correlates with tumor progression. This study implies that the invasion and metastasis suppressor function of E-cadherin may often be compromised in human prostate cancer by epigenetic rather than by mutational events.

Cadherins↗
PubMed2001

Scleral plug of biodegradable polymers containing ganciclovir for experimental cytomegalovirus retinitis.

PURPOSE: To evaluate the efficacy of a biodegradable scleral plug containing ganciclovir (GCV) in a rabbit model of human cytomegalovirus (HCMV) retinitis. METHODS: To develop a rabbit model for HCMV retinitis, HCMV solution was injected once into the vitreous cavity of pigmented rabbits. The treated animals were divided into three groups: group A received no treatment, group B was treated once with GCV solution, and group C was treated with a scleral plug containing GCV. Rabbits in group B received an intravitreal injection of GCV solution 1 week after HCMV inoculation. In group C, the scleral plug containing GCV was implanted in the vitreous of the rabbits 1 week after HCMV inoculation. Ophthalmoscopically, vitreoretinal findings in each group were graded from 0+ to 4+ every week for 4 weeks after HCMV injection. RESULTS: Eyes of group A rabbits showed whitish retinal exudates and vitreous opacities 3 days after HCMV inoculation. These materials increased gradually until 3 weeks after HCMV inoculation. Scores for vitreoretinal lesions were significantly lower in eyes of group B rabbits compared with those of group A at 1 week after GCV injection (P < 0.05). However, vitreoretinal inflammation in eyes of group B rabbits increased again thereafter, and no significant difference in inflammation between groups A and B was found 2 weeks after GCV injection. In eyes of group C, scores for vitreoretinal lesions were significantly lower compared with those in both group A and group B at 3 weeks after HCMV inoculation (P < 0.01). CONCLUSIONS: The results demonstrated that sustained release of GCV into the vitreous cavity with biodegradable scleral plugs was effective for the treatment of experimentally induced HCMV retinitis in rabbits.

Absorbable Implants↗
PubMed2001

No involvement of Erk/MAP kinases in IL-6-induced proliferation of a B cell hybridoma cell line.

Interleukin-6 (IL-6) is a pleiotropic cytokine and acts as a growth factor for murine plasmacytoma and human myeloma. IL-6 activates multiple signal transduction pathways. Among them, signal transducer and activator of transcription3 (STAT3), and the SHP-2-mediated Erk/MAP kinase pathway are important. The roles for the two major pathways in the IL-6-induced growth of B cell hybridoma cells were examined. A mutational analysis of the cytoplasmic domain of exogenously expressed gp130, a signal transducing beta chain of the IL-6 receptor complex, revealed that the proximal 133 amino acid (AA) region of gp130 with the intact Y767 but not Y759 is necessary and sufficient for gp130-signal-induced cell proliferation. Interestingly, no requirement of the Y759-mediated signals, including SHP-2-mediated Erk/MAP kinase pathway, coincided with the failure of SHP-2, Gab1/Gab2, and Erk/MAP kinase activation by IL-6 in MH60 cells. Moreover, we show that another serine/threonine kinase pathway leading to STAT3 Ser727 phosphorylation, which seemed to be derived from the Y767 in the proximal 133 AA residues, is intact in MH60 cells. Since Erk/MAP kinases are known to inhibit the subsequent IL-6-induced STAT3 activation, the impaired activation of Erk/MAP kinases by IL-6 may contribute to the development of B cell neoplasia.

B-Lymphocytes↗
PubMed2001

[A rabbit model for human cytomegalovirus retinitis].

PURPOSE: To develop a rabbit model for human cytomegalovirus(HCMV) retinitis. METHODS: 0.1 ml of 1 x 10(6) plaque forming units/ml HCMV was injected into the vitreous cavity of 10 pigmented rabbit eyes. The eyes were examined ophthalmoscopically on days 1, 2, 3, 4 and 7 and once a week thereafter until 4 weeks after inoculation. Vitreal and retinal findings were graded from 0+ to 4+ on a scale of increasing severity. In addition, we examined the enucleated eyes 3 weeks after HCMV inoculation by histological and immunohistochemical techniques. RESULTS: All injected eyes developed vitreoretinal lesions. Vitreous opacities appeared the next day and increased until 4 days after HCMV inoculation. Whitish retinal exudates occurred on day 3 and increased until 3 weeks after HCMV inoculation. Vitreoretinal lesions then disappeared by 4 weeks after inoculation. Histological examination revealed intraretinal infiltration of inflammatory cells and disorganization of the inner retinal architecture. HCMV antigens were detected inside the retina by immunofluorescence using anti early protein antibody against HCMV. CONCLUSIONS: The results indicate that this rabbit model can be useful to develop and evaluate a new treatment modality for cytomegalovirus retinitis.

Animals↗
PubMed2001

(99m)Tc-sestamibi retention characteristics during pharmacologic hyperemia in human myocardium: comparison with coronary flow reserve measured by Doppler flowire.

UNLABELLED: The aim of the study was to investigate the increase in myocardial (99m)Tc-methoxyisobutylisonitrile (sestamibi) retention in humans during pharmacologic vasodilation. METHODS: For calculation of the increase in (99m)Tc-sestamibi retention during hyperemia, baseline and adenosine triphosphate (ATP)-induced hyperemic stress sestamibi studies were performed using a same-day rest-stress protocol. On the injection of sestamibi, left ventricular dynamic data were obtained for 90 s. The increase in sestamibi retention from baseline to hyperemia was calculated by the formula [abstract: see text] where Cm(h)(t) and Cm(b)(t) are myocardial counts on the tomographic image, and Cb(b)(tau) and Cb(h)(tau) are the left ventricular blood-pool counts during the first transit of sestamibi at baseline and during hyperemia, respectively. Coronary flow increase during intravenous ATP stress was measured using intracoronary Doppler flow guide wire and compared with the scintigraphic results of 28 measurements in 22 patients. RESULTS: Sestamibi retention increased as coronary flow velocity increased but plateaued at >2.5-3 times baseline flow velocity. The relationship between the increase in sestamibi retention (Y) and the increase in flow (X) is expressed as follows: Y = 0.44 + 0.60X - 0.068X(2) (r = 0.82). CONCLUSION: In humans, the increase in (99m)Tc-sestamibi myocardial retention underestimates coronary flow reserve, particularly at high flow rates. Knowledge of these tracer retention characteristics will contribute to a more comprehensive understanding of the manner and interpretation of stress sestamibi imaging.

Adenosine Triphosphate↗
PubMed2001

Accuracy of ventricular volume and ejection fraction measured by gated myocardial SPECT: comparison of 4 software programs.

UNLABELLED: Gated myocardial perfusion SPECT has been used to calculate ejection fraction (EF) and end-diastolic volume (EDV) and has correlated well with conventional methods. However, the comparative accuracy of and correlations across various types of gated SPECT software are not well understood. METHODS: Mathematic phantoms of cylindric-hemispheric hybrid models, ranging in volume from 34 to 266 mL, were generated. The clinical cases consisted of 30 patients who participated in a radionuclide angiography and gated blood-pool (GBP) study in addition to undergoing (99m)Tc-sestamibi gated SPECT. Four kinds of software, Quantitative Gated SPECT (QGS), the Emory Cardiac Toolbox (ECT), 4D-MSPECT, and Perfusion and Functional Analysis for Gated SPECT (pFAST) were used to compute EF and EDV, and the results were analyzed by multiple comparisons tests. Patients were classified into 4 groups (i.e., no defect, small defect, large defect, and small heart) so that factors affecting variation could be analyzed. RESULTS: In mathematic models > or = 74 mL, volume error was within +/-15%, whereas for a small volume (34 mL), QGS and 4D-MSPECT underestimated the volume and pFAST overestimated it. The respective intra- and interobserver reproducibility of the results was good for QGS (r = 0.99 and 1.00), ECT (r = 0.98 and 0.98), and 4D-MSPECT (r = 0.98 and 0.98) and fair for pFAST (r = 0.88 and 0.85). The correlation coefficient for EF between gated SPECT and the GBP study was 0.82, 0.78, 0.69, and 0.84 for QGS, ECT, 4D-MSPECT, and pFAST, respectively. The correlation coefficient for EDV between gated SPECT and the GBP study was 0.88, 0.89, 0.85, and 0.90, respectively. Although good correlation was observed among the 4 software packages, QGS, ECT, and 4D-MSPECT overestimated EF in patients with small hearts, and pFAST overestimated the true volume in patients with large perfusion defects. Correlation coefficients among the 4 kinds of software were 0.80-0.95 for EF and 0.89-0.98 for EDV. CONCLUSION: All 4 software programs showed good correlation between EF or EDV and the GBP study. Good correlation was observed also between each pair of quantification methods. However, because each method has unique characteristics that depend on its specific algorithm and thus behaves differently in the various patient subgroups, the methods should not be used interchangeably.

Coronary Circulation↗